A retired Department of Corrections officer who spent about a decade working at the Arkansas Valley Correctional Facility says he's concerned for the safety of current officers. He spoke exclusively with News 5 after Monday's deadly attack on prison employees.

33-year-old Miguel Alonso Contreras-Perez is accused in the brutal attack that killed Sergeant Mary Ricard and seriously injured Sergeant Lori Gann on Monday. Contreras-Perez has been moved to a maximum security facility. The attack happened early Monday morning while breakfast was being prepared. Contraras-Perez -- who is a former Fort Carson soldier -- was serving 35 years to life. The Arkansas Valley Correctional Facility remains on lockdown as the investigation moves forward.

David Roberts retired this summer from the Department of Corrections; following Monday's attack, he called News 5 to talk about issues he and other officers had been seeing for a while. Now that he's retired, Roberts says he's not afraid to speak out.

"Why contact us at all on this?" News 5 asks Roberts.

"Because I'm concerned about the safety of the staff working there, and I saw things that were building up." explains Roberts; that's after 22 years working in the Department of Corrections and nearly a decade of that spent at the Arkansas Valley Correctional Facility.

Roberts is worried about administratively segregated inmates being transferred to that facility.

"The main reason an inmate is put in Ad-Seg is institutional behavior; be it assaults, gang, or whatever," explains Roberts. "Ark Valley got a big influx of those inmates; the problem being Ark Valley was designed and built as a medium security facility."

Roberts says they're being transferred from other state prisons in Sterling and Centennial. He says the staffing hasn't increased to address it.

"I know staff that are still working at Ark Valley I've talked to; they work in constant fear now," says Roberts.

"Before I retired, in July, the unit I worked in on day shifts is normally a staffing of three officers; one in the box control center and two on the floor," Roberts explains. "Routinely one of the officers would have to go help or strip-out or whatever, so that left one officer on the ground with over 200 inmates in one unit."

He says that's not a comfortable feeling.

"I've been there and done that, it gives you the warm fuzzies," says Roberts. "It can go south for no reason."

On Monday, after the attack, we asked Governor John Hickenlooper about staffing at the Arkansas Valley Correctional Facility.

"Based on what we do at other facilities and what our outcomes are, we certainly don't think it's understaffed, but we're certainly also going to examine that," says Gov. Hickenlooper.

However, Roberts says there aren't nearly enough officers.

"It can be a very scary environment to work in," says Roberts.

News 5 reached out to Department of Corrections for answers to Roberts' questions, but they haven't returned our calls as of this posting. When we receive an answer we'll post it for you on KOAA.com.